PPT97: Windows Metafiles Used as Textures Appear Large On Screen (160218)

SYMPTOMS

If you use a Windows Metafile (.wmf) as a texture, and then apply that texture to a slide background or to a PowerPoint drawing object, the texture appears very large on screen. When you print the slide, the texture prints at a more appropriate size.

CAUSE

PowerPoint converts a vector-based graphic internally to a bitmap graphic. To ensure that the graphic prints well, PowerPoint converts the vector-based graphic to a 576 dots per inch (dpi) bitmap. For example, PowerPoint converts a 1-inch x 1-inch vector-based graphic to a 576-pixel x

576-pixel bitmap. When PowerPoint displays the graphic, one pixel of the graphic appears the same as one screen pixel. A 576-pixel square graphic covers most of the screen if your display resolution is 640 x 480 pixels.

When you print the slide, the texture also prints at 576 dpi. Therefore, if you print to a 600 dpi printer, one repeat of the texture per inch is printed.

RESOLUTION

As a rule of thumb, a graphic makes a good texture if it measures from approximately 150 pixels square to about 250 pixels square. If you have a program that converts vector-based graphics to bitmap graphics, use it to convert the vector-based graphic to a bitmap graphic containing less than 250 pixels x 250 pixels. When you use that bitmap graphic as a texture, it will appear in a more appropriate size on your screen.

As an alternative, you can use the program to shrink the vector-based graphic so that it is less than about one-half inch square and save it under a different file name. Then, if you use that picture as a texture it will appear in a more appropriate size on your screen.